How do you weigh a growing polar bear?

How do you weigh a growing polar bear who is playful and frisky without having to render him unconscious to get him on the scales?

Staff at Highland Wildlife Park have an answer. They tried to weigh Walker the polar bear who was about 248kg (39 stone) when he arrived in December 2010. He is now thought to be about 400kg (63 stone).

Craig Anderson reports.